Officials with the Winnebago County, Illinois Health Department say more tests must be done before evacuated residents can return to their homes in Rockton.
Fire officials are asking those people for patience as the hazards from the fire at the Chemtool plant are assessed.
People living within a one-mile radius of the plant have been forced out of their homes.
Toxic chemicals have been stopped from leaking into nearby waterways, but there are remaining questions about air quality.
Rockton Fire Protection District Chief Kirk Wilson says the original estimate that the fire could burn for another seven days has been reduced.
